Highly unique Celtic progressive rockers Tempest have now begat an offspring, two-fifths of the band, leader Lief Sorbye and manic fiddler Michael Mullen finally filling a multitude of fan requests for a Caliban project. What is Caliban? Lief explains (sort of): "Caliban is a character in the Shakespeare play The Tempest, who sometimes appears as a villain and a servant, and sometimes appears in a mask. Servant, mask, villain . . it all applies. People that are hip to Shakespeare get it right away, not like we're big Shakespeareans (laughs)."

But Caliban is also the Tempest duo's "pure folk project", or more pointedly a heart-warming gathering of acoustic singsongs, featuring both originals and traditionals, rendered close, quiet and deeply rooted in history.

"We'd been doing quite a number of shows throughout the last year in and around the San Francisco area and have built up a bit of demand for it. It started off because we're working musicians and wanted to play more intimate settings, simply for a sense of diversity. We've ended up playing festivals where Tempest headlines, and Caliban play on a secondary stage, but so far Caliban has been more of a local project. So for the album, we took the songs our fanbase said they wanted to hear on record, and recorded it in the same sort of intimate, relaxed setting as our performances, trying to stick to an intimate live feel as opposed to a big production. It's more of a down-home folk album than anything progressive rock. A traditional folk music album. It's more of a pure setting, versus the rock environment we have with Tempest."

But the Tempest experience has definitely had an effect on the sensibilities of Caliban. Through two Magna Carta releases ('96's Turn Of The Wheel and '97's The Gravel Walk), Tempest have built themselves into an international touring act. And before Tempest (after his emigration from Norway to California in '81), Sorbye spent eight years with traditional Celtic act Golden Bough, as well as releasing two solo albums, "Spring Dans" and "Across The Borders". A lifetime of dedication.

So the Caliban record is a whirlwind tour of flavors building on this rich legacy of courting the Celtic muse, Sorbye's sonorous storyteller vocals and meticulous octave-mandola countering Mullen's ever-flowing fiddle patterns, creating a singular synergy of Lief's Norwegian heritage, Michael's grounding in country and classical, and the duo's shared love of Scottish and Irish musics. "Yes, Michael was classically trained, playing in youth orchestras and stuff," recounts Lief. "But where he's from, the Fresno area, the music that goes over very well is country music, so he played a fair bit of that, which has given him a lot of diversity of style. And with that, he's also built up a lot of Celtic techniques based on his Irish heritage, and taken it from there."

"The record's a mix of stuff," Lief offers. "I sing one song, 'Jeg Lagde Meg Sa Silde', in my native Norwegian language. It's an old 16th century ballad I've known for many years, which I rearranged for this recording. It's a diversity of ethnic roots really, because we've got everything from a Scottish march, to Irish reels, dance tunes. We've got a Norwegian song, a British murder ballad done acappella, and then we've got some contemporary songs, so it's definitely a cross-section."

Standout tracks include two traditional pieces 'Bold John Barleycorn' and 'The Journeyman', bluegrass-tinted Billy Connoly tune 'Oh No', plus a Richard Thompson composition called 'Beeswing', which Lief figures is his favorite on the record. "I'm particularly fond of that one because it really came off naturally, easy and relaxed. A lot of this is first takers, and I felt on that one, for some reason, I was able to relate the story with the right amount of passion." Mullen also figures prominently on borrowed viola.

So the Caliban record endeavors to capture the sense of communion shared at a robust, but soft-footed, folk-rooted Celtic concert. "Yes, in a way, this is a document of the live experience. Michael's a guy that gets very involved in his playing when he's on stage. He's a true showman and the two of us can stir up quite a bit of energy on our own. So we wanted to create the record very quickly and spontaneously to hopefully capture that."

Also integral to the record was Tempest producer Robert Berry (recording took place at Soundtek Studios in Campbell, California), who efficiently harnessed the band's energy, meeting effortlessly the particular production and mixing demands of acoustic instruments, as well as adding a bit of bass, guitar and keyboards.